As noted by FOSS Patents, Lodsys, the company that started suing app developers over alleged patent infringement for in-app purchases and upgrade buttons back in May, has amended its complaint including more companies allegedly infringing on their patents, like Rovio.  Lodsys has left out Vietnamese company Wulven Games from the suit, but has now included other bigger names like the makers of Angry Birds, EA, Atari, Square Enix, and Take-Two Interactive. In total, Lodsys is now suing 37 defendants – smaller independent companies like The Iconfactory were first sent notices by Lodsys in May.

Lodsys is still not impressed by Apple’s assertion that its own license to Lodsys’s patents extends to its app developers. I also pointed out that Apple’s “exhaustion” theory is not necessarily accurate. Also, Lodsys may be able to capitalize on contractual commitments that might preclude Apple and Google from challenging Lodsys’s patents and the related infringement allegations.

With today’s amended complaint, Lodsys is currently suing a total of 37 defendants, and there may be more to come.

In the first weeks of June, Apple filed a motion to intervene in the proceedings between Lodsys and app developers hit by the patent infringement claims – which Apple claimed have no basis as Apple is “indisputably licensed” to the patents, and the app makers are protected by the development agreement with Apple. Florian Mueller at FOSS Patents doesn’t seem to share a similar view, and we recommend you check out all the updates and timeline of events over at his blog.